XCOM: Enemy Unknown free-to-play this weekend on Steam

The preview is available now and will end at 6pm (BST) on Sunday, September 13, 2015.

If you enjoy your trial and fancy jumping into the game for realsies,
you’ll be able to pick it up for 75 percent off and retain any progress
made over the weekend.

2K has also confirmed pre-order incentives for the upcoming XCOM 2.
Pre-purchasers will secure the Resistance Warrior Pack, which will
offer additional soldier customisation options including bonus outfits,
facial war paint, as well as a Survivor of the Old War new recruit.